International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / Real-time computation speed is an additional requirement for simulations. It is necessary for 'man-in-the-loop' systems like flight simulators and for 'hardware-in-the-loop' systems where real components like new closed loop controllers are tested under realistic conditions. In the past a lot of companies have designed and built special purpose simulation computers which are very powerful but expensive and not handy enough for 'in-the-field-tests'. The progress in computer science shows a trend to distributed systems where multiple processors are running in parallel to improve the performance dramatically. At the DLR Institute for Flight Mechanics a computer system, based on the transputer, was designed to achieve the real-time simulation capabilities for the ROTEST model rotor. This four-bladed rotor is a 2.5 scale of the BO105 main rotor, equipped with elastic blades, operating at 1050 rpm. After an introduction to the ROTEST rotor, including the demands upon the simulation, a short introduction to transputers and the associated philosophy is given. The next part of the paper presents the characteristics of the simulation model, its mathematical description and the transputer architecture on which it is running. In the last part of the paper the input and output processes to the simulation are described. This includes a real-time representation of the rotor and an oscilloscope like output device, as well as analogue input and output devices to a controller.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Functional integration and validation of complex systems in an operational environment, prior to delivery or installation, can be expensive. Real-time simulation, in a lab environment, can replace hardware subsystems to provide the interfaces necessary to validate and or integrate the test article. The test article can be hardware, software or firmware. Multitasking simulations can provide modeling of subsystems and environmental sensor data for complex system integration. The simulation presented provides the capability to integrate 1553 remote terminals and provide validation of 1553 bus controller software.

A physical control/protection platform needs to be tested and its functionality verified prior to installation and commissioning. Closed-loop testing of a physical control/protection platform, in a real-time simulator environment is practically the only option to safely and thoroughly verify the design integrity and evaluate its functionality and performance. Moreover, a real-time simulator is also required to conduct statistical switching studies, as it substantially reduces the total run time of the study. This thesis proposes and develops a generalized methodology for implementation of the power system equations in the FPGA environment. The developed methodology enables real-time operation, for closed-loop testing of physical control/protection platforms in hardware-in-the-loop (HIL) configuration, and even faster-than-real-time operation, for statistical switching studies. Based on the developed methodology, an FPGA-based simulator is developed and tested. The salient features of the proposed implementation are: ² It enables the use of a nanosecond range simulation time-step to simulate large systems in real-time, in contrast to the us range time-steps used in the existing simulators. Thus it is also able to provide a wide frequency bandwidth for the simulation results. ² It retains the calculation time, within each simulation time-step, nearly fixed irrespective of the size of the system. ² It eliminates the need for the corrective measures, adopted in the existing real-time simulators, to reduce error due to the lack of synchronization between the simulation time-grid and the output signals of the control/protection platform under test. As an integral part of this work, this thesis proposes and develops the modified two-layer network equivalent (M-TLNE). The salient feature of the M-TLNE is its computational efficiency, as compared to the existing network equivalents, which makes it a prime choice for statistical switching studies and real-time simulation of electromagnetic transients. This thesis also proposes a generalized methodology, applicable to both single and multi-port network equivalents for both single- and multi-phase systems, for developing the proposed M-TLNE. The developed methodology ensures the stability and passivity of the M-TLNE.

A physical control/protection platform needs to be tested and its functionality verified prior to installation and commissioning. Closed-loop testing of a physical control/protection platform, in a real-time simulator environment is practically the only option to safely and thoroughly verify the design integrity and evaluate its functionality and performance. Moreover, a real-time simulator is also required to conduct statistical switching studies, as it substantially reduces the total run time of the study. This thesis proposes and develops a generalized methodology for implementation of the power system equations in the FPGA environment. The developed methodology enables real-time operation, for closed-loop testing of physical control/protection platforms in hardware-in-the-loop (HIL) configuration, and even faster-than-real-time operation, for statistical switching studies. Based on the developed methodology, an FPGA-based simulator is developed and tested. The salient features of the proposed implementation are: ² It enables the use of a nanosecond range simulation time-step to simulate large systems in real-time, in contrast to the us range time-steps used in the existing simulators. Thus it is also able to provide a wide frequency bandwidth for the simulation results. ² It retains the calculation time, within each simulation time-step, nearly fixed irrespective of the size of the system. ² It eliminates the need for the corrective measures, adopted in the existing real-time simulators, to reduce error due to the lack of synchronization between the simulation time-grid and the output signals of the control/protection platform under test. As an integral part of this work, this thesis proposes and develops the modified two-layer network equivalent (M-TLNE). The salient feature of the M-TLNE is its computational efficiency, as compared to the existing network equivalents, which makes it a prime choice for statistical switching studies and real-time simulation of electromagnetic transients. This thesis also proposes a generalized methodology, applicable to both single and multi-port network equivalents for both single- and multi-phase systems, for developing the proposed M-TLNE. The developed methodology ensures the stability and passivity of the M-TLNE.

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Physics engines become more and more common due to the rapid development and increasing demand of simulations. With this comes a need of testing the engine, a way to measure its performance, not only its speed but also its accuracy and stability. The purpose of this thesis has been to create a set of benchmark tests. They aim to check the physical aspects, especially mechanics, of the engine. A strategy and export functions for the test results in order to automate the testing have also been developed. The resulting tests became a beam on piles which analyses constraint stability, an overdetermined system consisting of a static door on multiple hinges, a falling object investigating the accuracy of the integrator, a box on an inclined plane for testing the friction model, a single pendulum as well as a multibody pendulum checking constraint accuracy and energy conservation, the Earth orbiting around the Sun which tests the stability of the integrator and finally a cantilever beam that is a static test of a real scenario. After the tests are performed the results are presented on an HTML-page. A prototype of a Web application is also established as well as a set of scalar tests that can be performed continuously, in order to follow trends or compare the engine's performance from time to time. This thesis was initialized by Algoryx Simulation AB which also provided the engine, AgX Dynamics, with the numerical method called SPOOK. It mainly performed well on all tests. In order to build a fully general toolbox more tests need to be added such as material interactions, scalable test with thousands of bodies, torque tests as well as more complex scenarios, for example a scissor lift and robots. The work can also be extended with more developed export functions, both to the Web and to documents. Hopefully this thesis can be seen as a complement to the earlier efforts done in creating a general set of benchmarks and automation framework for continuous integration and testing. / Fysikmotorer blir mer och mer vanliga på grund av den snabba utvecklingen och efterfrågan på simuleringar. I och med detta ökar också behovet av att testa motorerna och ett sätt att mäta prestandan, inte bara snabbheten utan också noggrannheten och stabiliteten. Syftet med detta examensarbete har varit att skapa ett set av prestandatester. De syftar till att testa de fysikaliska aspekterna av fysikmotorn, särskilt inom mekanik. En strategi och exportfunktioner för testresultaten för att automatisera testningen har också utvecklats. De resulterande testerna blev en balk på pålar som analyserar stabiliteten hos villkoren, ett överbestämt system bestående av en statisk dörr på flera gångjärn, ett fallande objekt som granskar precisionen hos integratorn, en låda på ett lutande plan som testar friktionsmodellen, en enkel pendel samt en flerkropppspendel som kontrollerar villkorsprecisionen och energikonservering, jordens bana runt solen som testar integratorns stabilitet och slutligen en utskjutande balk som är ett statiskt test av ett verkligt fall. När testerna är genomförda presenteras resultaten på en HTML-sida. En prototyp av en webb-applikation har också utvecklats samt ett set med skalära tester som kan utföras kontinuerligt för att följa upp trender och jämföra motorns prestanda över tid. Det här examensarbetet initierades av Algoryx Simulation AB som även tillhandahållit fysikmotorn, AgX Dynamics, med den numeriska metoden SPOOK. Motorn presterade överlag bra på testerna. För att bygga en allmän verktygslåda behövs fler tester så som interaktion mellan material, skalbara tester med tusentals kroppar samt mer komplexa simuleringar, t.ex. en saxlyft och robotar. Arbetet kan också utökas med mer utvecklade exportfunktioner, både mot webben och som dokument. Förhoppningsvis kan detta ses som ett komplement till de tidigare ansträgningar som gjorts för att skapa ett generellt set av prestandatester och ett automatiskt ramverk för kontinuerlig testning.

This thesis presents investigations into the effect of modern wind farms on grid side short circuits using extensive real time digital simulation. Particular reference is made to adaptive autoreclosing algorithms using artificial neural networks. A section of 132kV transmission grid in Scotland, including DFIG wind farms, is modelled on a real time digital simulator. An algorithm is then developed and tested using this model to show that this autoreclosing technique is feasible in systems with high penetration of wind generation. Although based on an existing technique, an important innovation is the use of two neural networks for the separate tasks of arc presence and extinction. The thesis also describes a low-cost, real time, relay development platform.

Real-time digital simulation of electrical machines and drives is an efficient approach to evaluate the true behavior of newly designed machines and controllers before applying them in a real system. State-of-the-art real-time digital simulators aim to offer a precise replica for different parts of an electrical drive. By the aid of these powerful simulators and hardware-in-the-loop (HIL) simulation, design engineers are able to test their new controllers or machines against a virtual motor drive which has been previously modeled and tested off-line. Interaction between different parts of the electrical drive, especially under hazardous and abnormal conditions, can then be studied in a cost-effective manner. Although many studies about the optimized models of power electronic drives and digital controllers for real-time simulation have been done, the real-time models of electrical machines are still limited to the lumped parameter electric circuit models. This is mainly due to the complexity of a detailed electrical machine model which makes it computationally expensive. In this thesis geometrical real-time permeance network models (PNMs) of induction machines are developed which can accommodate the local phenomena inside an electric machine such as saturation and slotting. For this purpose, numerical methods inside the model are optimized to reduce the computation time. Novel nonlinear solution algorithms are also developed to address the problem of real-time simulation of nonlinear systems. Next, the proposed model is linked with other parts of an electric drive to develop a PNM-based real-time induction motor drive. A comparison of the results obtained through real-time simulation and experiment shows their agreement. / Power Engineering and Power Electronics

Digital microprocessor based relays are currently being utilized for safe, reliable and efficient operation of power systems. The overcurrent protection relay is the most extensively used component to safeguard power systems from the detrimental effects of faults. Wrong settings in overcurrent relay parameters can lead to false tripping or even bypassing fault conditions which can lead to a catastrophe. Therefore it is important to validate the settings of power protection equipment and to confirm its performance when subject to different fault conditions. This paper presents the modeling of an overcurrent relay in SimPowerSystems (\textsc {matlab}/Simulink). The overcurrent relay has the features of instantaneous, time definite and inverse  definite minimum time (IDMT) characteristics. A power system is modeled in SimPowerSystems and this overcurrent relay model is incorporated in the test case. The overall model is then simulated in real-time using Opal-RT's eMEGAsim real-time simulator to analyze the relay's performance when subjected to faults and with different characteristic settings in the relay model. Finally Hardware-in-the-Loop validation of the model is done by using the overcurrent protection feature in Schweitzer Engineering Laboratories Relay SEL-487E. The event reports generated by the SEL relays during Hardware-in-the-Loop testing are compared with the results obtained from the standalone testing and software model to validate the model. / <p>QC 20130215</p>

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